The invention relates to random orbital sanders.
Random orbital sanders are commonly used for sanding, grinding, polishing and other types of surface treatment. One might typically find them in automotive shops and in other shops where finishing is done. Random orbital sanders are different from conventional rotary sanders and generally serve a different purpose. Whereas conventional rotary sanders are often used primarily for material removal and rough work, random orbital sanders are better suited for finish work requiring a finish without the circular scratches often caused by the rotary sander.
Random orbital sanders are so named because of the motion imparted to the sanding pad during operation. In a conventional rotary sander, the sanding pad assembly is attached directly to the rotating drive shaft of the tool and thus, the sanding pad rotates with the shaft to generate purely circular motion. In a random orbital sander, the sanding pad is attached to a second shaft that is parallel to, but offset from, the rotating drive shaft of the tool. The sanding pad is free to rotate about the axis of the second shaft independently of the rotation of the drive shaft. Since the second shaft, and thus the sanding pad, are eccentrically positioned relative to the drive shaft, the entire sanding pad assembly follows an orbital path when the drive shaft rotates. When the sanding pad of a random orbital sander is applied to a work surface, the sanding pad rotates about the second axis in a pattern dictated by the complex forces applied to the pad by the workpiece and which can best be described as random. Thus, the name random orbital sander.